You can group all available Cobra Jet style heads together such as Blue Thunder, D00E-R, TFS CJ, TFS Street Heat, Edelbrock CJ, Ford A-429, Ford SCJ, and P-51. Port them, same valves sizes and there won't be enough difference between them to pick one over the other.
One example I saw was a 514 with ported D00E-R heads. The owner switched to Ford SCJ's and went two tenths slower. Now to be fair these SCJ's were out of the box as cast. he had them ported and they ran the same as the iron CJ. There is just too much misinformation out there. You have to compare apples to apples or as close as you can get.
The only way you can see a 75 HP gain is to put a 390 cfm pair of any of the above in place of as cast 325 cfm heads.